System and interface for cross administration or technology domain network functions (NFS) instantiation and configuration for roaming users

ABSTRACT

An embodiment of the present invention relates to an operator management system in a first administrative domain for supporting a user roaming from the first administrative domain to a second administrative domain within a network architecture. The network architecture comprises a collection of interconnected network functions deployed in a control plane and a user plane, and the interconnected NFs comprise at least core network control plane functions and a core network user plane function. The OMS in the first administrative domain is configured to generate and issue to an OMS in the second administrative domain, a roaming management request for roaming a user from the first administrative domain to the second administrative domain, over an inter-operator management interface, and configured to instruct the OMS in the second administrative domain to configure the second administrative domain based on the roaming management request to support the user roaming.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/EP2017/079449, filed on Nov. 16, 2017, the disclosure of which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments of the present invention relate to the field of wirelesscommunications, and more particularly to user roaming across operatorsusing an inter-operator interface within a network slicing architecture.

BACKGROUND

According to the industry consensus, the 5th Generation (5G) mobiletechnology will be standardized and deployed by 2020. Compared to the4th Generation (4G) mobile technology, the devices and applications ofthe next generation network will support use cases with a very highdiversity in terms of performance attributes, such as ultra-reliablecommunications for mission critical services, eHealth, public safety,real-time vehicle control, tactile Internet and connectivity for drones.In order to support services with such a diverse range of requirements,the architecture fitting all the solutions used in the 4G network willbe not scalable for the myriad of different use cases. Thus, the networkslicing concept is expected to be one of the key building blocks of thefuture 5G network according to the recent standardization agreements.Indeed, the current understanding of the 5G architecture is that eachtype of device or application will have its own architectural slice,which will be configured just for their requirements. The device orapplication will be provided by a slice owner and hosted by an operator,and the slice owner will be a vertical or an Over-The-Top (OTT) providerof the device or application, so that the network slicing concept willenable a service-tailored network function provisioning scheme aiming inparticular at vertical industries integration.

According to the Technical Report (TR) entitled: 3GPP TR 28.801, “Studyon management and orchestration of network slicing for next generationnetwork”, V15.0.0 (2017-09), a network slice is composed of a collectionof logical Network Functions (NFs) that supports the communicationservice requirements of particular use case(s). On the other hand, theTechnical Specification (TS) entitled: 3GPP TS 23.501, “Systemarchitecture for the 5G system”, V1.4.0 (2017-09), defines a networkslice as a complete logical network that comprises a set of NFs andcorresponding resources, which are necessary to provide certain networkcapabilities and network characteristics. A network slice may includeboth an Access Network (AN) and a Core Network (CN), and a Network SliceInstance (NSI) may be defined as the instantiation of a network slice,i.e., as a deployed set of NFs delivering the intended network sliceservices.

The support of network slicing is enabled by the architecturemodularization design principle stating that the 5GS referencearchitecture features the core network decomposition into orthogonalsets of NFs for Control Plane (CP or C-plane) and User Plane (UP orU-plane). The CP NFs are classified as Common Control NFs (CCNFs) andSlice-specific Control NFs (SCNFs), in order to distinguish between theNFs that may be shared among multiple NSIs and those that areNSI-specific.

Many users may frequently roam from one operator to another one. Inparticular, support for vehicle-to-X (V2X)-like use cases may also implythat, for some users, an operator can predict when a car would leave itscoverage area and enter another area covered by other operators.

As disclosed in the above-mentioned 3GPP TS 23.501, differentnon-roaming and roaming reference architectures may be considered.

FIG. 1 shows a non-roaming 5G system architecture using a service-basedinterface representation within the CP. Therein, all NFs deployed in theCP (i.e., all CP NFs) and in the UP (i.e., all UP NFs) belong to a sameadministrative domain like, for example, a Public Land Mobile Network(PLMN), which may also be denoted as a Home PLMN (HPLMN, also denoted ashPLMN) since there is no user roaming.

As therein depicted, the 5G system architecture may consist of thefollowing CP NFs and CP entities:

-   -   Network Slice Selection Function (NSSF);    -   Network Exposure Function (NEF);    -   NF Repository Function (NRF);    -   Policy Control function (PCF);    -   Unified Data Management (UDM);    -   Application Function (AF);    -   Authentication Server Function (AUSF);    -   Access and Mobility Management Function (AMF);    -   Session Management Function (SMF).

Those CP NFs are capable of delivering a respective service and areinterconnected to other CP NFs being authorized to access theirservices, via service-based interfaces denoted as Nxxx (e.g., Naf,Nausf, Namf and so on) for the CP NF denoted as xxx (e.g., AF, AUSF, AMFand so on).

Furthermore, the 5G system architecture may consist of the following CNNFs and CN entities:

-   -   User Plane Functions (UPFs);    -   User Equipment (UE);    -   (Radio) Access Network ((R)AN);    -   Data Network (DN), e.g., operator services, Internet access or        third party services.

The functional description of these CP NFs, CP entities, CN NFs and CNentities may be found in clause 6 of 3GPP TS 23.501, V1.4.0 (2017-09).

As further depicted, the 5G system architecture may also includepoint-to-point reference points denoted as Ni, where i=1, 2, 3, . . . .Thus, the UE, which is connected to the (R)AN via an access interface,may be connected to the AMF via a N1 interface. The (R)AN may beconnected to the AMF via a N2 interface and to the UPF via a N3interface. The UPF may be connected to the SMF via a N4 interface and tothe DN via a N6 interface.

Except for the DN, which is external to the HPLMN, and the AF, which maybe provided by a third party, all NFs belong to the same HPLMN and aretherefore managed by a same Home Operator Management System (HOMS) (alsodesignated as Home Operator's Management System).

FIG. 2 shows a roaming 5G system architecture using the service-basedinterface representation within the CP in the case of a Local Break-Out(LBO) scenario with the AF in a Visited or Visitor PLMN (VPLMN, alsodenoted as vPLMN).

For that LBO scenario, in comparison with the non-roaming referencearchitecture of FIG. 1, all UPFs belong to the VPLMN and some CP NFs aresplit between the VPLMN and the HPLMN. In particular, the UDM and theAUSF belong to the HPLMN only, while the NRF, the PCF and the NEF areduplicated both in the VPLMN and the HPLMN, while the NSSF, the AMF, theSMF and the AF belong to the VPLMN only.

Furthermore, the (R)AN and the DN belong to the VPLMN, so that theconnections between the (R)AN and the UPF via the N3 interface andbetween the UPF and the DN via the N6 interface occur in the VPLMN.

FIG. 3 shows a roaming 5G system architecture using the service-basedinterface representation within the CP in the case of a LBO scenariowith AF in the HPLMN.

This LBO scenario differs from that of FIG. 2 only in that the AF nowbelongs to HPLMN.

FIG. 4 shows a roaming 5G system architecture using the service-basedinterface representation within the CP in the case of a Home Routed (HR)scenario.

For that HR scenario, all UPFs belong both to the VPLMN and the HPLMN,wherein the N6 interface between the UPF and the DN is terminated in theHPLMN. Some CP NFs are split between the VPLMN and the HPLMN. Inparticular, the UDM, the AUSF and the AF belong to the HPLMN only, whilethe NRF, the PCF, the NEF and the SMF are duplicated both in the VPLMNand the HPLMN, while the NSSF and the AMF belong to the VPLMN only.

Furthermore, the (R)AN belongs to the VPLMN, so that the connectionbetween the (R)AN and the UPF in the VPLMN via the N3 interface occursin the VPLMN, while the UPF in the VPLMN is also connected to the UPF inthe HPLMN via a N9 interface.

For each roaming scenario of FIGS. 2 to 4, it may be assumed that theVPLMN and HPLMN are respectively managed by a distinct NetworkManagement System (NMS), which may be referred to as a Visited orVisitor NMS (VNMS) for the VPLMN and a Home NMS (HNMS) for the HPLMN.This assumption is presented in 3GPP TR 28.801, V15.0.0 (2017-09) andbased on the fact that the definition of VPLMN and HPLMN originates fromdifferent owners having different management systems.

Further, it can be readily observed that the roaming scenarios representparticular deployments, in which an end-to-end (E2E) network slice spansacross different PLMNs, i.e., across different administrative domains.

However, a NF in the HPLMN has no information about or no awareness ofthe NFs in the VPLMN and vice versa. It results therefrom that, in 5G, afirst look-up shall be performed by the VPLMN in order to identify theHPLMN that is responsible for the UE, followed by a second look-up to beperformed by said HPLMN in order to find the NF(s) in the HPLMNresponsible for serving the UE.

The first look-up is rather straightforward in Long Term Evolution(LTE), because the UE Subscriber Identity Module (SIM) is capable ofspecifying a priority list with the Mobile Country Code (MCC) followedby the Mobile Network Code (MNC) in the HPLMN selector with AccessTechnology (AT). The same applies to 5G. However, the LTE-like solutionis too static with respect to the billions of connected devices in 5Gand the ability to support a dynamic re-configurability.

The second lookup is currently carried out by NFs in the HPLMN.

The problem with the current definition of the 5G systems combined withthe incumbent requirement of operating network slices spanning acrossmultiple PLMNs (i.e., HPLMNs and/or VPLMNs) is that such cases areassumed to be handled merely as roaming scenarios, which may render theE2E slice performance requirements difficult to meet. In thisconnection, the key limitations of the roaming scenarios may, forexample, be a limited visibility and accessibility by the VPLMN CP NFs(e.g., AMF) and the HPLMN CP NFs (e.g., NSSF, NRF) that are essential tonetwork slices operations, a limited visibility and accessibility by theVPLMN and HPLMN CP NFs of the UPFs, thereby impairing the ability ofmonitoring and enforcing the E2E Quality of Service (QoS), and a need toinvolve the HPLMN CP NFs to access information (e.g., registration,session management procedures, mobility management procedures) necessaryto complete E2E slicing related procedure.

Such key limitations are deemed to be performance critical. Indeed, theE2E procedure shall disadvantageously require supplementaryVPLMN-to-HPLMN signaling, such as SMFs duplication in VPLMN and/or HPLMNand credential retrieval at AUSF in HPLMN (i.e., at hAUSF) among others.In addition, the E2E procedure may be disadvantageously affected byextra latency/delay when the VPLMNs and HPLMNs are, for example,connected via transoceanic connections, satellite links and/or thirdparty networks, thereby rendering the possibility of running delaysensitive applications across such operators difficult.

SUMMARY

It is therefore an object of embodiments of the present invention toallow an efficient user roaming across operators or operator managementsystems (OMSs).

The object is achieved by the features of the independent claims.Further embodiments of the invention are apparent from the dependentclaims, the description and the drawings.

In one aspect, an embodiment of the invention relates to an operatormanagement system (OMS) (also designated as operator's managementsystem) in a first administrative domain (e.g., HPLMN) for supporting auser roaming from the first administrative domain to a secondadministrative domain (e.g., VPLMN) within a network architecture. TheOMS in the first administrative domain may be configured to generate andissue to an OMS in the second administrative domain, a roamingmanagement request for roaming a user (e.g., UE) from the firstadministrative domain to the second administrative domain, over aninter-operator management interface (OP-OP interface), and configured toinstruct the OMS in the second administrative domain to configure thesecond administrative domain based on the roaming management request tosupport the user roaming. The network architecture may comprise acollection of interconnected network functions (NFs) deployed in acontrol plane (CP) and a user plane (UP), and the interconnected networkfunctions (NFs) may comprise at least core network control planefunctions (CN-CPFs) and a core network user plane function (CN-UPF).

Thereby, the UP and CP performance in roaming scenarios can be optimizedin terms, for example, of latency and reliability, due to the usage of“local” (i.e., located in the VPLMN) instances of CP and UP functions insuch roaming scenarios, the roaming user (e.g., UE) being controlled bythe VPLMN NFs while being still under the management of the HPLMN. Thisleads to better support the roaming of the user by possibly achieving afaster authorization, a local break-out and a reduced inter-PLMNsignaling.

In one embodiment, inside the OMS in the first administrative domain,the roaming management request may be generated by a long-term data anduser behavior analysis program having the capability of identifying theroaming user as a high probability roaming user.

In one embodiment, the OMS may comprise at least one management functionentity amongst a service management function (SMF) entity, a networkslice management function (NSMF) entity, a network slice subnetmanagement function (NSSMF) entity and an infrastructure managementfunction (IMF) entity, and comprise at least one delegation entityconfigured to delegate the roaming management request to thecorresponding management function entity of the OMS in the secondadministrative domain. The management function entity may be configuredto manage a respective managed entity being one amongst a sub-service orservice when the management function entity is the SMF, a network sliceinstance (NSI) or network slice when the management function entity isthe NSMF, a network slice subnet instance (NSSI) or network slice subnetwhen the management function entity is the NSSMF and an infrastructurewhen the management function entity is the IMF, the infrastructurecomprising network functions (NFs), virtualized network functions (VNFs)and basic resources. The delegation entity may be configured to be anend-point of the OP-OP interface between the OMS in the firstadministrative domain and the OMS in the second administrative domain.And the roaming management request may be provided by the OMS in thefirst administrative domain at a managed entity layer to the OMS in thesecond administrative domain at a corresponding managed entity layer,wherein a delegation entity of the OMS in the second administrativedomain may receive the roaming management request and delegate theroaming management request to a corresponding managed entity of the OMSin the second administrative domain.

It shall be noted that the management function entities (i.e., CSMF,SMF, NSMF, NSSMF, IMF) may be separated from or collocated/grouped withany other management function entities inside the corresponding OMS. Ifcollocated/grouped, the individual functionalities inside a group ofmanagement function entities may then be combined into a single overallfunctionality.

It shall be further noted that the term “delegate” may be used here inthe sense of “transmit after analysis of the incoming request followedby a selection of the management function entity”.

It shall be also noted that the delegation entity may be separated fromthe management function entities or collocated with at least onemanagement function entity inside the corresponding OMS.

In one embodiment, the roaming management request may compriseconfiguration parameters and/or deployment parameters.

It shall be noted that the above-mentioned term “parameter(s)” may beinterchangeably used with the term “argument(s)” in embodiments of thepresent invention.

In one embodiment, the roaming management request may be a request forconfiguring a first NF (e.g., vNRF) in the second administrative domain(e.g., VPLMN) corresponding to a second NF (e.g., hNRF) in the firstadministrative domain (e.g., HPLMN), based on the configurationparameters in order to connect the first NF in the second administrativedomain to the second NF in the first administrative domain.

In one embodiment, the configuration parameters may comprise at leastone amongst a list of user identifications (e.g., UE IDs) for which therequested configuration is valid, a user group identification (e.g., acaller subscriber group ID) for which the requested configuration isvalid, services and/or slices for which the requested configuration isvalid, and an address of the second NF (e.g., hNRF) in the firstadministrative domain (e.g., HPLMN).

In one embodiment, the roaming management request may be a request forinstantiating and configuring a third NF (e.g., pNRF) in the secondadministrative domain (e.g., VPLMN) corresponding to a fourth NF (e.g.,hNRF) in the first administrative domain (e.g., HPLMN), based on theconfiguration parameters in order to connect the third NF in the secondadministrative domain to the fourth NF in the first administrativedomain.

In one embodiment, the third NF in the second administrative domain maybe a proxy NF.

In one embodiment, the configuration parameters may comprise at leastone amongst a list of user identifications (e.g., UE IDs) and servicesfor which the requested configuration is valid, an address of the fourthNF (e.g., hNRF) in the first administrative domain (e.g., HPLMN), animage of the third NF (e.g., pNRF), instructions for onboarding and lifecycle management, and instructions and parameters for performancemanagement (PM), fault management (FM) and configuration management (CM)of the third NF (e.g., pNRF).

In one embodiment, the roaming management request may be a request forembedding a fifth NF (e.g., hAUSF) of the first administrative domain(e.g., HPLMN) into the second administrative domain (e.g., VPLMN) byinstantiating and configuring the fifth NF in the second administrativedomain based on the configuration parameters in order to interconnectthe embedded fifth NF (e.g., pAUSF) with the NFs in the secondadministrative domain.

In one embodiment, the configuration parameters may comprise at leastone amongst a list of user identifications (e.g., UE IDs) and servicesfor which the requested configuration is valid, an address of the fifthNF (e.g., hAUSF) in the first administrative domain (e.g., HPLMN), animage of the embedded fifth NF (e.g., pAUSF), instructions foronboarding and life cycle management, and instructions and parametersfor performance management (PM), fault management (FM) and configurationmanagement (CM) of the embedded fifth NF (e.g., pAUSF).

In one embodiment, the roaming management request may be a request forembedding a sixth NF (e.g., hNRF) of the first administrative domain(e.g., HPLMN) into a seventh NF (e.g., vNRF) in the secondadministrative domain (e.g., VPLMN) by instantiating and configuring thesixth NF in the seventh NF, based on the configuration parameters.

It shall be noted that the sixth NF may be instantiated in the seventhNF as a part of the seventh NF if created from the seventh NF or, ifotherwise created, as a separate entity with respect to the seventh NF.

In one embodiment, the configuration parameters may comprise at leastone amongst a list of user identifications (e.g., UE IDs) for which therequested configuration is valid, a user group identification (e.g., acaller subscriber group ID) for which the requested configuration isvalid, services and/or slices for which the requested configuration isvalid, and an address of the sixth NF (e.g., hNRF) in the firstadministrative domain (e.g., HPLMN).

In one embodiment, the OMS in the first administrative domain may beconfigured to request a deployment, at the corresponding managed entitylayer, of at least one managed entity in the OMS in the secondadministrative domain, the deployment being based on the deploymentparameters, and configured to request a configuration, at thecorresponding managed entity layer, to the OMS in the secondadministrative domain, the configuration being based on theconfiguration parameters to use the deployed managed entity.

In one embodiment, the CN-CPFs may comprise at least one amongst anaccess and mobility management function (AMF), a session managementfunction (SMF), a policy control function (PCF), a network exposurefunction (NEF), a network repository function (NRF), a unified datamanagement (UDM), an authentication server function (AUSF), anapplication function (AF), and a network slice selection function(NSSF).

The above object is also solved in accordance with another embodiment.

According to another aspect, an embodiment of the invention relates toan operator management system (OMS) (also designated as operator'smanagement system) in a third administrative domain (e.g., VPLMN) forsupporting a user roaming from a fourth administrative domain (e.g.,HPLMN) to the third administrative domain within a network architecture.The OMS in the third administrative domain may be configured to receive,from an OMS in the fourth administrative domain, a roaming managementrequest for roaming a user (e.g., UE) from the fourth administrativedomain to the third administrative domain, over an inter-operatormanagement interface (OP-OP interface), and configured to configure thethird administrative domain based on the received roaming managementrequest to support the user roaming.

The above object is also solved in accordance with another embodiment.

According to another aspect, an embodiment of the invention relates to asystem within a network architecture. The system may at least comprisean operator management system (OMS) (also designated as operator'smanagement system) in an administrative domain (e.g., HPLMN) as claimedin the embodiment and/or any one of the implementation forms of theembodiment, and an operator management system (OMS) (also designated asoperator's management system) in another administrative domain (e.g.,VPLMN) as claimed in another embodiment. Each OMS may communicate toeach other over an inter-operator management interface (OP-OPinterface).

The above object is also solved in accordance with another embodiment.

According to another aspect, an embodiment of the invention relates to amethod for supporting a user roaming from a first administrative domain(e.g., HPLMN) to a second administrative domain (e.g., VPLMN) within anetwork architecture. The method may be performed at an operatormanagement system (OMS) (also designated as operator's managementsystem) in the first administrative domain and comprise the operationsof generating and issuing to an OMS in the second administrative domain,a roaming management request for roaming a user (e.g., UE) from thefirst administrative domain to the second administrative domain, over aninter-operator management interface (OP-OP interface), and the operationof instructing the OMS in the second administrative domain to configurethe second administrative domain based on the roaming management requestto support the user roaming. The network architecture may comprise acollection of interconnected network functions (NFs) deployed in acontrol plane (CP) and a user plane (UP), and the interconnected networkfunctions (NFs) may comprise at least core network control planefunctions (CN-CPFs) and a core network user plane function (CN-UPF).

In one embodiment, the method may comprise the operation of requesting adeployment, at a managed entity layer, of at least one managed entity inthe OMS in the second administrative domain, the deployment being basedon the deployment parameters, and the operation of requesting aconfiguration, at the managed entity layer, to the OMS in the secondadministrative domain, the configuration being based on theconfiguration parameters to use the deployed managed entity.

The above object is also solved in accordance with another embodiment.

According to another aspect, an embodiment of the invention relates to amethod for supporting a user roaming from a fourth administrative domain(e.g., HPLMN) to a third administrative domain (e.g., VPLMN) within anetwork architecture. The method may be performed at an operatormanagement system (OMS) (also designated as operator's managementsystem) in the third administrative domain and comprise the operation ofreceiving, from an OMS in the fourth administrative domain, a roamingmanagement request for roaming a user (e.g., UE) from the firstadministrative domain to the second administrative domain, over aninter-operator management interface (OP-OP interface), and the operationof configuring the third administrative domain based on the receivedroaming management request to support the user roaming.

The above object is also solved in accordance with another embodiment.

According to another aspect, an embodiment of the invention relates to acomputer program comprising a program code for performing the methodaccording to any one of the embodiments and their respectiveimplementation forms when executed on a computer.

Thereby, the method can be performed in an automatic and repeatablemanner.

The computer program can be performed by the above apparatuses.

In particular, it should be noted that all the above apparatuses may beimplemented based on a discrete hardware circuitry with discretehardware components, integrated chips or arrangements of chip modules,or based on a signal processing device or chip controlled by a softwareroutine or program stored in a memory, written on a computer-readablemedium or downloaded from a network such as the Internet.

It shall further be understood that an embodiment of the invention canalso be any combination of the dependent claims or above embodimentswith the respective independent claim.

These and other embodiments of the invention will be apparent andelucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, theinvention will be explained in more detail with reference to theexemplary embodiments shown in the drawings, in which:

FIG. 1 shows a non-roaming 5G system architecture using a service-basedinterface representation within the CP, according to 3GPP TS 23.501,V1.4.0 (2017-09);

FIG. 2 shows a roaming 5G system architecture using the service-basedinterface representation within the CP in the case of a LBO scenariowith AF in the VPLMN, according to 3GPP TS 23.501, V1.4.0 (2017-09);

FIG. 3 shows a roaming 5G system architecture using the service-basedinterface representation within the CP in the case of a LBO scenariowith AF in the HPLMN;

FIG. 4 shows a roaming 5G system architecture using the service-basedinterface representation within the CP in the case of a HR scenario;

FIG. 5 shows an OMS-to-OMS interface for multi-operator NSI creation,according to 3GPP TR 28.801, V15.0.0 (2017-09);

FIG. 6 shows a schematic bloc diagram of an operator A in anadministrative domain (depicted as VPLMN) receiving an external servicerequest from an operator B in another administrative domain (depicted asHPLMN) over an inter-operator management interface (depicted as OP-OPinterface);

FIG. 7 shows a schematic diagram illustrating a configuration and/ordeployment of NFs to support a user roaming, according to an embodimentof the present invention;

FIG. 8 shows a direct vNRF-to-hNRF connectivity within the roaming 5Gsystem architecture of FIG. 2, according to an embodiment of the presentinvention;

FIG. 9 shows a direct proxy vNRF-to-hNRF connectivity within the roaming5G system architecture of FIG. 2, according to an embodiment of thepresent invention;

FIG. 10 shows a hAUSF (depicted as pAUSF) as embedded into the VPLMNwithin the roaming 5G system architecture of FIG. 2, according to anembodiment of the present invention;

FIG. 11 shows a hNRF as embedded into the vNRF within the roaming 5Gsystem architecture of FIG. 2, according to an embodiment of the presentinvention.

Identical reference signs are used for identical or at leastfunctionally equivalent features.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In embodiments of the present invention, a network slice, alsodesignated as a slice, will be defined as a collection of interconnectedlogical access network (AN) functions and core network (CN) functionscapable of meeting a diverse range of requirements.

In addition, business roles will be played by a customer, a serviceprovider, a slice provider, a partial slice provider and aninfrastructure provider.

The customer may be defined as a final customer whose role is to requestand own the service. Then, the customer may, for example, sell theservice to service end-users. The customer may comprise a customerservice management function (CSMF) entity as a management functionentity. The CSMF entity may be configured to manage the service as amanaged entity.

The service provider may play the same role as a traditional operator byproviding a sub-service or service as well as the virtualized networkfunctions (VNFs) and the complete design of the sub-service itself tothe customer. The service provider may comprise a service managementfunction (SMF) entity as a management function entity. The SMF entitymay be configured to manage the sub-service or service as a managedentity.

The role of the slice provider may be to create and operate the sliceand provide it to the service provider. The slice provider may comprisea network slice management function (NSMF) entity as a managementfunction entity. The NSMF entity may be configured to manage a networkslice instance (NSI) or network slice as a managed entity.

The role of the partial slice provider may be to provide parts of theslice to the slice operator. The partial slice provider may comprise anetwork slice subnet management function (NSSMF) entity as a managementfunction entity. The NSSMF entity may be configured to manage a networkslice subnet instance (NSSI) or network slice subnet as a managedentity, the NSSI or slice subnet being a part of the NSI or networkslice.

The role of the infrastructure provider may be similar to that of theowner of the actual physical infrastructure. The infrastructure providermay comprise an infrastructure management function (IMF) entity as amanagement function entity. The IMF entity may be configured to managean infrastructure as a managed entity, by managing and orchestrating thenetwork functions (NFs), the virtualized network functions (VNFs) andthe basic physical or virtual resources (e.g., compute, storage andnetworking).

According to 3GPP standards, an operator can expose interfaces to otheroperators. In particular, FIG. 5 shows an OMS-to-OMS interface (i.e., aninter-operator management interface between the operator A and theoperator B, which may also be designated as OP-OP interface) formulti-operator NSI creation, according to 3GPP TR 28.801, V15.0.0(2017-09). Therein, the customer requests a communication service forrealizing an NSI to a single OMS (i.e., to the operator A). Then, theCommunication Service Management Function (CSMF) hosted in the operatorA decides to use the NSMF of another OMS (i.e., of the operator B) torealize the NSI. In this particular case, the operator A exposes aninterface to the operator B during the life cycle management of the NSI,the operator A being responsible for the management of the NSI in theoperator B. In a non-limitative embodiment, the operator A may also beresponsible for the management of any other managed entities (e.g.,NSSI, infrastructure) in the operator B.

FIG. 6 shows a schematic bloc diagram of an operator A in anadministrative domain (depicted as VPLMN) receiving an external servicerequest from an operator B in another administrative domain (depicted asHPLMN) over an inter-operator management interface (depicted as OP-OPinterface).

As an OMS, each operator may comprise at least one delegation component(designated hereafter as delegation entity), at least one SMF, at leastone NSMF, at least one NSSMF and at least one IMF.

The delegation entity may be configured to delegate an incoming requestfrom an operator at a managed entity layer to a management functionentity of another operator corresponding to the managed entity layer. Inembodiments of the present invention, the incoming request may be aroaming management request for roaming a user (e.g., a UE) from anoperator to another one. In FIG. 6, the delegation entity of theoperator A may delegate the external service request as the incomingrequest from the operator B at a specific managed entity layer (amongstthe SMF, NSMF, NSSMF and IMF layers) to a management function entity ofthe operator A corresponding to the specific managed entity layer. Inother terms, the delegation entity of the operator A may perform ananalysis of the incoming request followed by a selection of anappropriate management function entity, and then transmit the incomingrequest to the selected management function entity.

In addition, the delegation entity may be configured to be an end-pointof the OP-OP interface between the operator B (i.e., the OMS in theHPLMN) and the operator A (i.e., the OMS in the VPLMN). In particular,the end-point may provide a programmable interface in the operator inwhich it is hosted (e.g., the operator A when referring to FIG. 6) toany other operator (e.g., the operator B when referring to FIG. 6).

In an OMS, the delegation entity may be separated from the managementfunction entities or collocated with at least one management functionentity inside the OMS.

Any of these management functions (e.g., SMF, NSMF, NSSMF, IMF) may beseparated from or collocated/grouped with any other management functionentity. If collocated/grouped, the individual functionalities inside agroup of management function entities may then be combined into a singleoverall functionality.

In embodiments of the present invention, the incoming request may be aroaming management request for roaming at least one user (e.g., UE) froman administrative domain (e.g., a HPLMN), to which the operator Bbelongs, to another administrative domain (e.g., VPLMN), to which theoperator A belongs, within a network architecture. Such a networkarchitecture may be based on one of the roaming reference architecturesas disclosed in 3GPP TS 23.501, V1.4.0 (2017-09). Only for the sake ofsimplicity, the network architecture will refer, in a non-limitativeembodiment, to the roaming 5G system architecture of FIG. 2, unlessotherwise indicated.

FIG. 7 shows a schematic diagram illustrating a configuration and/ordeployment of NFs to support a user roaming, according to an embodimentof the present invention.

Therein, a roaming management request, for roaming at least one user(e.g., UE) from the HPLMN to the VPLMN within the roaming 5G systemarchitecture of FIG. 2, is generated by the operator B (as an OMS in theHPLMN), and issued from the operator B to the operator A (as an OMS inthe VPLMN) over the OP-OP interface (i.e., the inter-operator managementinterface), in order to instruct the operator A to configure at leastone NF in its PLMN (i.e., VPLMN) based on configuration parameterscontained in the roaming management request in order to support the userroaming, and/or in order to deploy at least one NF in its PLMN (i.e.,VPLMN) based on deployment parameters contained in the roamingmanagement request in order to support the user roaming.

Prior to achieving the configuration and/or the deployment, the operatorA in the VPLMN may check that the requested configuration and/ordeployment are allowable and not conflicting with the existingconfigurations in the VPLMN. If any detected conflict, the operator A inthe VPLMN may then signal the corresponding failure to the detectedconflict to the operator B in the HPLMN.

At a layer or level of the management function entities depicted as SMF,NSMF, NSSMF and IMF, the operator B in the HPLMN may request arespective deployment of new services, slices, slice subnets and/orphysical or virtual infrastructure including NFs at a layer or level ofthe corresponding management function entities in the operator A in theVPLMN. The operator B in the HPLMN may then instruct the operator A inthe VPLMN to configure the NFs in the VPLMN to use the deployedinfrastructure to host the at least one user (e.g., UE).

In a first embodiment, the present invention allows to create a directconnectivity between NF instance(s) in the VPLMN and NF instance(s) inthe HPLMN, namely between vNF(s) and hNF(s). This direct connectivitymay be provided via dedicated high reliability and high speed links andallows to create logical NFs whose instances are actually deployedacross the different administrative domains (i.e., across HPLMN andVPLMN). Over the OP-OP interface, the OMS in the HPLMN (also denoted ashPLMN MS) interacts with the OMS in the VPLMN (also denoted as vPLMNMS). The IMF in the VPLMN (denoted as vIMF) and the IMF in the HPLMN(denoted as hIMF) create a direct link between hNF(s) and vNF(s).

Only for illustrative purposes, in the non-limitative case where the NFto be configured is the NRF, FIG. 8 shows a direct vNRF-to-hNRFconnectivity within the roaming 5G system architecture of FIG. 2,according to an embodiment of the present invention.

Over the OP-OP interface (depicted by a numbered circle with the number“2”), the hPLMN MS may instruct the vPLMN MS to configure the vNRF(i.e., NRF in the VPLMN) corresponding to the hNRF (i.e., NRF in theHPLMN), by issuing to the vPLMN MS a roaming management requestcomprising configuration parameters. The requested configuration willconsist in connecting the hNRF and the vNRF based on the followingconfiguration parameters comprising at least one amongst a list of useridentifications (e.g., UE IDs) for which the requested configuration isvalid, a user group identification (e.g., a caller subscriber group ID)for which the requested configuration is valid, services and/or slicesfor which the requested configuration is valid, and an address of thehNRF in the HPLMN.

Once the roaming management request has been received over the OP-OPinterface, the vPLMN MS may then locally configure the NRF (i.e., vNRF)based on the received configuration parameters. The internalconfiguration may be performed through any combination of delegationentity-to-SMF, delegation entity-to-NSW, delegation entity-to-NSSMF anddelegation entity-to-IMF interfaces (depicted by the numbered circleswith the numbers “1” for HPLMN and “3” for VPLMN). Again, the delegationentity may be separated from the management function entities orcollocated with at least one management function entity.

Still for illustrative purposes, in the non-limitative case where the NFto be configured is the AMF, the hPLMN MS may instruct the vPLMN MS toconfigure the vAMF (i.e., AMF in the VPLMN) corresponding to the hAMF(i.e., AMF in the HPLMN) only for specific UE IDs and/or services, byforwarding the roaming management request directly to a respective NRFand/or SMF. For example, if a specific slice is only available in theHPLMN, then the AMF may directly access the corresponding SMF in theHPLMN (i.e., hSMF).

In a second embodiment, the present invention allows the hPLMN MS tointeract with the vPLMN MS over the OP-OP interface, in order toinstantiate a proxy NF in the VPLMN and to create a direct connectivitybetween the instantiated proxy NF in the VPLMN and the corresponding NFin the HPLMN, the proxy NF being instantiated by the vIMF.

For illustrative purposes, in the non-limitative case where theinstantiated proxy NF in the VPLMN is the proxy NRF (also denoted asproxy vNRF), FIG. 9 shows a direct proxy vNRF-to-hNRF connectivitywithin the roaming 5G system architecture of FIG. 2, according to anembodiment of the present invention.

Over the OP-OP interface (depicted by a numbered circle with the number“2”), the hPLMN MS may instruct the vPLMN MS to instantiate andconfigure, in the VPLMN, the proxy NRF (i.e., proxy vNRF, depicted aspNRF in the VPLMN) corresponding to the hNRF (i.e., NRF in the HPLMN),by issuing to the vPLMN MS a roaming management request comprisingconfiguration parameters. The requested configuration will consist inconnecting the hNRF and the pNRF based on the following configurationparameters comprising at least one amongst a list of useridentifications (e.g., UE IDs) and services for which the requestedconfiguration is valid, an address of the hNRF in the HPLMN, an image ofthe pNRF, instructions for onboarding and life cycle management, andinstructions and parameters for performance management (PM), faultmanagement (FM) and configuration management (CM) of the pNRF.

Once the roaming management request has been received over the OP-OPinterface, the vPLMN MS may then locally instantiate and configure thepNRF based on the received configuration parameters. The internalconfiguration may be performed through any combination of delegationentity-to-SW, delegation entity-to-NSW, delegation entity-to-NSSMF anddelegation entity-to-IMF interfaces (depicted by the numbered circleswith the numbers “1” for HPLMN and “3” for VPLMN). Again, the delegationentity may be separated from the management function entities orcollocated with at least one management function entity.

In a third embodiment, the present invention allows the hPLMN MS tointeract with the vPLMN MS over the OP-OP interface, in order to embedan NF of the HPLMN (i.e., a hNF) into the VPLMN by instantiating the hNFdirectly in the VPLMN. The embedded hNF is managed (indirectly) by thehPLMN MS and interconnected with the NFs in the VPLMN in the same manneras an “ordinary” vNF. The vIMF instantiates, under the direct managementof the hPLMN MS, the hNF to be embedded.

For illustrative purposes, in the non-limitative case where the embeddedhNF in the VPLMN is the hAUSF, FIG. 10 shows the hAUSF as embedded intothe VPLMN within the roaming 5G system architecture of FIG. 2, accordingto an embodiment of the present invention.

Over the OP-OP interface (depicted by a numbered circle with the number“1”), the hPLMN MS may instruct the vPLMN MS to embed the hAUSF into theVPLMN and configure the embedded hAUSF, by issuing to the vPLMN MS aroaming management request comprising configuration parameters, whichare similar to those of the second embodiment.

Once the roaming management request has been received over the OP-OPinterface, the vPLMN MS may then locally instantiate and configure thehAUSF based on the received configuration parameters. The internalconfiguration may be performed through any combination of delegationentity-to-SMF, delegation entity-to-NSW, delegation entity-to-NSSMF anddelegation entity-to-IMF interfaces (depicted by the numbered circlewith the number “2” for VPLMN). Again, the delegation entity may beseparated from the management function entities or collocated with atleast one management function entity.

In a fourth embodiment, the present invention allows the hPLMN MS tointeract with the vPLMN MS over the OP-OP interface, in order to embedan NF of the HPLMN (i.e., a hNF) into an NF of the VPLMN (i.e., a vNF)by instantiating the hNF directly in the vNF. The embedded hNF, whichmay be considered an agent of the corresponding hNF in the vNF, ismanaged (indirectly) by the hPLMN MS and interconnected with the NFs inthe VPLMN in the same manner as an “ordinary” vNF. The vIMFinstantiates, under the direct management of the hPLMN MS, the hNF to beembedded.

It shall be noted that the hNF to be embedded may be instantiated in thevNF as a part of this vNF if created from this vNF or, if otherwisecreated, as a separate entity with respect to this vNF.

For illustrative purposes, in the non-limitative case where the embeddedhNF in the VPLMN is the hNRF, FIG. 11 shows the hNRF as embedded intothe vNRF within the roaming 5G system architecture of FIG. 2, accordingto an embodiment of the present invention.

Over the OP-OP interface (depicted by a numbered circle with the number“1”), the hPLMN MS may instruct the vPLMN MS to embed the hNRF into thevNRF and configure the embedded hNRF, by issuing to the vPLMN MS aroaming management request comprising configuration parameters, whichare similar to those of the first embodiment.

Once the roaming management request has been received over the OP-OPinterface, the vPLMN MS may then locally instantiate and configure thehNRF based on the received configuration parameters. The internalconfiguration may be performed through any combination of delegationentity-to-SW, delegation entity-to-NSW, delegation entity-to-NSSMF anddelegation entity-to-IMF interfaces (depicted by the numbered circlewith the number “2” for VPLMN). Again, the delegation entity may beseparated from the management function entities or collocated with atleast one management function entity.

It shall be noted that the vPLMN MS may restrict the HPLMN over theOP-OP interface to modify only the limited part of the vNRF that it isallowed to.

In return, the VPLMN exposes a direct management interface to the HPLMNto manage directly the hNRF embedded into the vNRF. The return over theOP-OP interface comprises at least one amongst the access credentialsand the ID to access the hNRF embedded into the vNRF, the options tomodify it or delete it, and the current entries in the hNRF.

It shall be noted that any combination of those first, second, third andfourth embodiments may be possible. In an exemplary combination, theHPLMN may configure the NRF in the VPLMN and, at the same time,configure the AMF in the VPLMN to connect directly to the SMF in theHPLMN for another service.

In summary, embodiments of the present invention relate to an OMS in afirst administrative domain (e.g., HPLMN) for supporting a user roamingfrom the first administrative domain to a second administrative domain(e.g., VPLMN) within a network architecture. The network architecturecomprises a collection of interconnected NFs deployed in a CP and a UP,and the interconnected NFs comprise at least core network control planefunctions (CN-CPFs) and a core network user plane function (CN-UPF). TheOMS in the first administrative domain is configured to generate andissue to an OMS in the second administrative domain, a roamingmanagement request for roaming a user (e.g., UE) from the firstadministrative domain to the second administrative domain, over aninter-operator management interface (OP-OP interface), and configured toinstruct the OMS in the second administrative domain to configure thesecond administrative domain based on the roaming management request tosupport the user roaming. In particular, the network architecture may bea roaming 5G system architecture as found in 3GPP TS 23.501, and theroaming solution of using the OP-OP interface to configure details ofthe user in the second administrative domain (e.g., VPLMN) within such anetwork architecture may be applied, for example, for users thatfrequently visit the second administrative domain (e.g., VPLMN), and/orwhen the number of HPLMN communicating with VPLMN is very large (i.e.,exceeds a given threshold), and/or for slices in which the users requirea very low delay.

While embodiments of the present invention have been illustrated anddescribed in detail in the drawings and the foregoing description, suchillustration and description are to be considered illustrative orexemplary and not restrictive. The invention is not limited to thedisclosed embodiments. From reading the present disclosure, othermodifications will be apparent to a person skilled in the art. Suchmodifications may involve other features, which are already known in theart and may be used instead of or in addition to features alreadydescribed herein.

The invention has been described in conjunction with various embodimentsherein. However, other variations to the disclosed embodiments can beunderstood and effected by those skilled in the art in practicing theclaimed invention, from a study of the drawings, the disclosure and theappended claims. In the claims, the word “comprising” does not excludeother elements or operations, and the indefinite article “a” or “an”does not exclude a plurality. A single processor or other unit mayfulfill the functions of several items recited in the claims. The merefact that certain measures are recited in mutually different dependentclaims does not indicate that a combination of these measures cannot beused to advantage. A computer program may be stored/distributed on asuitable medium, such as an optical storage medium or a solid-statemedium supplied together with or as part of other hardware, but may alsobe distributed in other forms, such as via the Internet or other wiredor wireless telecommunication systems.

Although embodiments of the present invention has been described withreference to specific features and embodiments thereof, it is evidentthat various modifications and combinations can be made thereto withoutdeparting from the spirit and scope of the invention. The specificationand drawings are, accordingly, to be regarded simply as an illustrationof the invention as defined by the appended claims, and are contemplatedto cover any and all modifications, variations, combinations orequivalents that fall within the scope of the present invention.

What is claimed is:
 1. An operator management system (OMS) in a firstadministrative domain for supporting a user roaming from the firstadministrative domain to a second administrative domain within a networkarchitecture, the OMS in the first administrative domain comprising: atleast one management function entity among a service management function(SMF) entity, a network slice management function (NSMF) entity, anetwork slice subnet management function (NSSMF) entity, and aninfrastructure management function (IMF) entity; and at least onedelegation entity configured to delegate a roaming management request toa corresponding management function entity of the OMS in the secondadministrative domain, wherein the OMS in the first administrationdomain is configured to: generate and issue to an OMS in the secondadministrative domain, the roaming management request for roaming a userfrom the first administrative domain to the second administrativedomain, over an inter-operator management interface (OP-OP interface);and instruct the OMS in the second administrative domain to configurethe second administrative domain based on the roaming management requestto support the user roaming, wherein the network architecture comprisesa collection of interconnected network functions (NFs) deployed in acontrol plane (CP) and a user plane (UP); and wherein the interconnectedNFs comprise at least: core network control plane functions (CN-CPFs);and a core network user plane function (CN-UPF).
 2. The OMS of claim 1,wherein the management function entity is configured to manage arespective managed entity amongst a sub-service or service when themanagement function entity is the SMF, a network slice instance (NSI) ornetwork slice when the management function entity is the NSMF, a networkslice subnet instance (NSSI) or network slice subnet when the managementfunction entity is the NSSMF and an infrastructure when the managementfunction entity is the IMF, the infrastructure comprising networkfunctions (NFs), virtualized network functions (VNFs), and basicresources; wherein the delegation entity is configured to be anend-point of the OP-OP interface between the OMS in the firstadministrative domain and the OMS in the second administrative domain;and wherein the roaming management request is provided by the OMS in thefirst administrative domain at a managed entity layer to the OMS in thesecond administrative domain at a corresponding managed entity layer, adelegation entity of the OMS in the second administrative domainreceiving the roaming management request and delegating the roamingmanagement request to a corresponding managed entity of the OMS in thesecond administrative domain.
 3. The OMS of claim 2, wherein the roamingmanagement request comprises at least one of configuration parameters ordeployment parameters.
 4. The OMS of claim 3, wherein the roamingmanagement request is a request for configuring a first NF in the secondadministrative domain corresponding to a second NF in the firstadministrative domain, based on the configuration parameters in order toconnect the first NF in the second administrative domain to the secondNF in the first administrative domain.
 5. The OMS of claim 3, whereinthe roaming management request is a request for instantiating andconfiguring a third NF in the second administrative domain correspondingto a fourth NF in the first administrative domain, based on theconfiguration parameters in order to connect the third NF in the secondadministrative domain to the fourth NF in the first administrativedomain.
 6. The OMS of claim 3, wherein the roaming management request isa request for embedding a fifth NF of the first administrative domaininto the second administrative domain by instantiating and configuringthe fifth NF in the second administrative domain based on theconfiguration parameters in order to interconnect the embedded fifth NFwith the NFs in the second administrative domain.
 7. The OMS of claim 3,wherein the roaming management request is a request for embedding asixth NF of the first administrative domain into a seventh NF in thesecond administrative domain by instantiating and configuring the sixthNF in the seventh NF, based on the configuration parameters.
 8. The OMSof claim 3, which is further configured to: request a deployment, at thecorresponding managed entity layer, of at least one managed entity inthe OMS in the second administrative domain, the deployment being basedon the deployment parameters; and request a configuration, at thecorresponding managed entity layer, to the OMS in the secondadministrative domain, the configuration being based on theconfiguration parameters to use the deployed managed entity.
 9. The OMSof claim 1, wherein the CN-CPFs comprise at least one of: an access andmobility management function (AMF); a session management function (SMF);a policy control function (PCF); a network exposure function (NEF); anetwork repository function (NRF); a unified data management (UDM); anauthentication server function (AUSF); an application function (AF); ora network slice selection function (NSSF).
 10. An operator managementsystem (OMS) in a third administrative domain for supporting a userroaming from a fourth administrative domain to the third administrativedomain within a network architecture, the OMS in the thirdadministrative domain comprising: at least one management functionentity among a service management function (SMF) entity, a network slicemanagement function (NSMF) entity, a network slice subnet managementfunction (NSSMF) entity, and an infrastructure management function (IMF)entity; and at least one delegation entity configured to delegate aroaming management request to a corresponding management function entityof the OMS in the third administrative domain, wherein the OMS in thethird administrative domain is configured to: receive, from an OMS inthe fourth administrative domain, the roaming management request forroaming a user from the fourth administrative domain to the thirdadministrative domain, over an inter-operator management interface(OP-OP interface); and configure the third administrative domain basedon the received roaming management request to support the user roaming.11. A system, comprising: a first operator management system (OMS) in afirst administrative domain for supporting a user roaming from the firstadministrative domain to a second administrative domain within a networkarchitecture; and a second operator management system (OMS) in thesecond administrative domain for supporting the user roaming; whereinthe first OMS and the second OMS communicate to each other over aninter-operator management interface (OP-OP interface); and wherein thefirst OMS includes: at least one management function entity among aservice management function (SMF) entity, a network slice managementfunction (NSMF) entity, a network slice subnet management function(NSSMF) entity, and an infrastructure management function (IMF) entity;and at least one delegation entity configured to delegate a roamingmanagement request to a corresponding management function entity of theOMS in the second administrative domain, and wherein the first OMS isconfigured to: generate and issue to the second OMS, a roamingmanagement request for roaming a user from the first administrativedomain to the second administrative domain, over the inter-operatormanagement interface (OP-OP interface); and instruct the second OMSconfigure the second administrative domain based on the roamingmanagement request to support the user roaming, wherein: the networkarchitecture comprises a collection of interconnected network functions(NFs) deployed in a control plane (CP) and a user plane (UP); and theinterconnected NFs comprise at least: core network control planefunctions (CN-CPFs); and a core network user plane function (CN-UPF);the second OMS being configured to: receive, from the first OMS, theroaming management request for roaming the user from the firstadministrative domain to the second administrative domain, over theinter-operator management interface (OP-OP interface); and configure thesecond administrative domain based on the received roaming managementrequest to support the user roaming.
 12. The system of claim 11,wherein: the management function entity is configured to manage arespective managed entity amongst a sub-service or service when themanagement function entity is the SMF, a network slice instance (NSI) ornetwork slice when the management function entity is the NSMF, a networkslice subnet instance (NSSI) or network slice subnet when the managementfunction entity is the NSSMF and an infrastructure when the managementfunction entity is the IMF, the infrastructure comprising networkfunctions (NFs), virtualized network functions (VNFs), and basicresources; the delegation entity is configured to be an end-point of theOP-OP interface between the OMS in the first administrative domain andthe OMS in the second administrative domain; and the roaming managementrequest is provided by the OMS in the first administrative domain at amanaged entity layer to the OMS in the second administrative domain at acorresponding managed entity layer, a delegation entity of the OMS inthe second administrative domain receiving the roaming managementrequest and delegating the roaming management request to a correspondingmanaged entity of the OMS in the second administrative domain.
 13. Thesystem of claim 12, wherein the roaming management request comprises atleast one of configuration parameters or deployment parameters.
 14. Thesystem of claim 13, wherein the roaming management request is a requestfor configuring a first NF in the second administrative domaincorresponding to a second NF in the first administrative domain, basedon the configuration parameters in order to connect the first NF in thesecond administrative domain to the second NF in the firstadministrative domain.
 15. The system of claim 13, wherein the roamingmanagement request is a request for instantiating and configuring athird NF in the second administrative domain corresponding to a fourthNF in the first administrative domain, based on the configurationparameters in order to connect the third NF in the second administrativedomain to the fourth NF in the first administrative domain.
 16. Thesystem of claim 13, wherein the roaming management request is a requestfor embedding a fifth NF of the first administrative domain into thesecond administrative domain by instantiating and configuring the fifthNF in the second administrative domain based on the configurationparameters in order to interconnect the embedded fifth NF with the NFsin the second administrative domain.
 17. The system of claim 13, whereinthe roaming management request is a request for embedding a sixth NF ofthe first administrative domain into a seventh NF in the secondadministrative domain by instantiating and configuring the sixth NF inthe seventh NF, based on the configuration parameters.
 18. The system ofclaim 13, which is further configured to: request a deployment, at thecorresponding managed entity layer, of at least one managed entity inthe OMS in the second administrative domain, the deployment being basedon the deployment parameters; and request a configuration, at thecorresponding managed entity layer, to the OMS in the secondadministrative domain, the configuration being based on theconfiguration parameters to use the deployed managed entity.